DE202011001662U1 - Hutmutter - Google Patents

Abstract

A nut (10) having a polygonal base (16) with a central bore (18) provided with an internal thread and a dome-shaped cover (20) coaxial with the central internal bore (18) on one side of the base (16) is formed and has an inner diameter which is at least as large as the internally threaded central bore (18), characterized in that the dome-shaped cover (20) is provided on its inner side with a nose-shaped Anformung (22) which is arranged coaxially to the central bore is and in the interior of the dome-shaped cover (20) limited interior space (23) protrudes.

Description

The invention relates to a nut having a polygonal base body with a central bore which is provided with an internal thread, and with a dome-shaped cover, which is integrally formed coaxially to the inner bore on one side of the base body and having an inner diameter which is at least as large as that with Internally threaded central bore. Furthermore, the invention relates to a screw connection with a nut of the type described above.

Such specially designed screws are also known as cap nuts, there are different configurations here. In general, cap nuts or nuts are provided with a threaded hole to the outside closing cover where otherwise by the protruding threaded pin risk of injury to persons due to the sharp-edged thread or if the mother not form-fitting threaded protrusion protected from contamination and thus often accompanied by corrosion should.

So is out of the US 787154 A such a cap nut called "cap nut" known soft for use in motor vehicles and other uses is provided.

From the DE 4408733 A1 is known a cap nut, which is provided for attachment of windscreen wiper arms on the respective drive shaft. Furthermore, from the DE 4239583 C2 a mother with an outside cover known, which is spaced from the nut thread and so defines a cavity which serves to receive a sealing plug, which closes the threaded hole of the mother and should prevent the ingress of dirt or moisture into the mother.

All known cap nuts have in common that they are used, as previously mentioned, to protect protruding threads from contamination and to protect people from injury by the sharp-edged thread.

Not considered in all known cap nut constructions, the problem that may not be the desired determination of the relevant threaded pin, because the length of the relevant thread projection is greater than the required screwing depth of the cap nut, without this being noticed.

It is often possible, especially in the case of products with great diversity, in production only with considerable effort, to reliably rule out such faulty screw connections when using cap nuts. In particular, if the available screw-in depth only slightly less than the required screw-in depth, so that no air gap remains below the cap nut, this state can go undetected. This faulty mounting state can lead to serious malfunctions of machines or systems. For this reason, cap nuts can often not be used for safety-relevant screwed connections.

Based on this prior art, it is an object of the invention to provide a nut of the aforementioned type, are made visible in the faulty Verschraubungsfälle so that insufficient attachment or determination by cap nuts not undetected, but is brought to the display or reliably detected becomes.

This object is achieved by the characterizing features of claim 1.

Accordingly, the invention provides that the dome-shaped cover is provided on its inner side with a Anformung which is arranged coaxially to the central bore and protrudes into the bounded by the dome-shaped cover interior.

This Anformung shortens the distance between the end of the thread and the cover, wherein the provided in the nut according to the invention thread length is generally considered to be sufficient for the intended fixing by means of screwing, so that for a sufficient attachment only a small thread overhang in the inventive Threaded nut provided thread length is required.

The axial length of the molding is according to the specifications of the specific standards, for example DIN 78 , so dimensioned that the thread-side projection of the relevant screw or threaded pin is at least 2 × P with P = thread pitch, without this already comes to a contact between the Anformung and the end of the screw or the threaded pin.

This ensures that the structurally required holding force of the relevant screw or pin connection is securely transmitted from the cap nut according to the invention. Only when the thread-side projection is larger, the contact with the Anformung provided according to the invention and the deformation caused thereby accompany the dome-shaped cover of the cap nut according to the invention.

According to an advantageous embodiment of the invention, which is provided on the inside of the dome-shaped cover Anformung integrally formed thereon. This means that the Anformung proposed as Einschraubanzeige is permanently connected to the nut according to the invention and can not be lost.

According to an advantageous variant but can also be provided that the nose-shaped Anformung is added as a separate item by force and / or positively connected in the course of production with the nut body, for example by means of clamping or latching connection, or is glued.

According to this alternative embodiment, the dome-shaped cover with inner central nose-shaped Anformung is made separately for the purpose of simplified manufacture, for example as a pressing member, and then attached to the mother in question, so that the cap nut invention results.

In a further improvement of the invention, the nut according to the invention is characterized in that when screwing the provided in the base thread length exceeding screwing length of a screw, the screw acts on the inside of the dome-shaped cover forming force applied conclusive and thereby deforms the dome-shaped cover.

This has the effect that when screwing a nut according to the invention on a screw or a corresponding threaded member whose length is greater than the screwing of the nut, the end face of the threaded element contacted the molding and as a result of its feed and the resulting force the Anformung frontally acted upon and pushes outward, which leads to deformation of the dome-shaped cover. Such deformation can be recognized well and without special aids, so that faulty fastenings are avoided with the nuts according to the invention.

According to a particular embodiment, the dome-shaped cover may be provided with a mark, for example with a notch, which changes visibly as a result of the application of the dome-shaped cover Anformung by a screw with oversized thread length and so the excess length due to a large thread projection of a screwed threaded element, such as screw, threaded pin or threaded bolt indicates.

This is intended that the attached to the dome-shaped cover of the nut marking tears open when frictional action by the relevant threaded pin either as a result of wall weakening or at least clearly visible in appearance.

According to an alternative solution, it is provided that the dome-shaped cover is provided with a display mark which cooperates with the Anformung provided on the inside of the dome-shaped cover and upon application of the dome-shaped cover Anformung by a screw with oversized screw-in length, that is to the outside visible.

In this case, as a display mark, in particular a localized part is considered, which is acted upon directly by the inside molding and accordingly emerges selectively and so represents a visible disturbance of the dome surface, which can be both visually recognized as well as felt.

According to the nut according to the invention, the polygonal base body is designed as a hexagon, so that it can be easily mounted.

It also proves to be advantageous if the dome-shaped cover is integrally formed on the base body. However, the dome-shaped cover may also be non-positively and / or positively connected to the base body, in the case of a faulty Schraubbefestigung the entire dome-shaped cover is separated from the body and due to the resulting annular gap between the base body and the dome-shaped cover of the error is displayed.

A further advantageous embodiment of the nut according to the invention is characterized in that the polygonal base body is provided on its dome-shaped cover opposite end face with a flange-like extension, whereby the bearing surface of the nut is increased.

Here, the support surface of the flange-like extension may be provided with a roughened surface structure, such as corrugation or ribbing, which is additionally effective as a positive locking screw, wherein according to a preferred embodiment, the corrugation or ribbing is provided radially on the support surface of the flange extension. In this context, under corrugation is a uniform groove-shaped surface structure understood, the groove depth is less than 1 mm, while ribbing a similar profiling is understood in which, however, the height of the individual ribs is greater than 1 mm.

In summary, it should be noted that with the present invention, a well practicable way is created to avoid faulty screwing or reliably detect the occurrence of misguided by visual and / or tactile control and then to provide relief.

This is inventively achieved in that a measurable deformation of the nut material occurs, if the allowable screwing when screwing the nut is exceeded on a thread projection.

A deformation of the closed side of the cap nut according to the invention as a signal function for a faulty mounting state should attract attention of the fitter, even if the visibility is unfavorable. For this purpose, the invention provides that the dome-shaped cover deforms so that you can feel this deformation anyway, if the lighting conditions make it difficult to visual control or even do not allow. Thus, to simplify detection of the desired deformations of the nut according to the invention, an additional component may be applied on its outer side in the deformable region, which either protrudes from the dome-shaped cover when deformed by a screwed-in threaded bolt or at least partially opens it.

In the event that so designed according to the invention nuts are also used for large through holes or to reduce the surface pressure is provided to the base on the dome-shaped cover opposite side to form a flange, which can also serve as a screw lock with appropriate design.

In addition, it proves to be advantageous if the nut according to the invention in addition to the signal function also fulfills the requirement sealing against liquid and gaseous media. For this purpose, it may be provided to provide the nut according to the invention with a sealing element, preferably at the inner flange radius.

These and other advantageous embodiments and improvements of the invention are the subject of the dependent claims.

Reference to an embodiment of the invention shown in the accompanying drawings, the invention, advantageous embodiments and improvements of the invention and particular advantages of the invention will be explained and described in detail.

Show it:

1 a nut according to the invention with flange in the half-sided longitudinal section;

2a an example of a screw connection of two parts by means of the inventive nut according to 1 with a screw of suitable length, that is with correct thread projection;

2 B an example of a screw connection of two parts by means of the inventive nut according to 1 with a screw with excess length, that is with too large thread projection and

3 a nut according to the invention with flange and / or sealing ring in the half-sided longitudinal section.

In 1 is a nut according to the invention 10 shown in half-sided longitudinal section, that is, the right half in the figure 12 shows the sectional view, with the left half 14 a side view of the nut according to the invention 10 represents.

The inventive nut 10 is as a cap nut with a sechskanfförmigen body 16 with a threaded hole 18 and an immediately following dome-shaped Anformung 20 formed, which the nut according to the invention 10 hat-like closes and leads to the designation of the nut according to the invention as a cap nut. Accordingly, the dome-shaped cover 20 also as a hat 20 designated.

The representation in 1 shows on the left half 14 the outer contour of an inventively designed cap nut, which is provided with a flange, while the sectional view of the right half 12 a nose 22 reveals which centric, that is coaxial with the threaded hole 18 on the inside of the dome-shaped cover 20 is molded and in the of the dome-shaped cover 20 limited interior 23 protrudes.

In addition, the inventively designed cap nut 10 with a flange-like edge 24 provided on the dome-shaped cover 20 opposite side of the body 16 is formed

This nose 22 acts on the one hand as a mechanical Einschraubbegrenzung and also serves as an indicator for a proper fitting, as in a screw with a screw with excess length this nose 22 inevitably contacted and mechanically acted upon. This action turns the nose 22 against the inside of the dome-shaped cover 20 applied and urges them with simultaneous deformation to the outside.

For the purposes of the invention, the outer surface of the dome-shaped cover 20 prepared in such a way that an attached cross-like mark 26 , which in 2 is shown, is irreversibly changed by the deformation and the visually made visible difference from the normal state as a sign of an inadmissible thread projection, for example due to an overlong screw, is to be regarded.

This cross may, for example, be a notch in the nut, which optically changes as a result of the deformation when the nose-shaped formation meets on the inside of the dome-like cover and the end of the screw. Instead, it can also be a color mark, which is changed in mechanical appearance in their appearance.

Furthermore, the mark may also be a very firmly adhering sticker, similar to, for example, a highway vignette prepared separation points, which cause the tearing of the sticker at these locations with already slight deformation of the dome of the screw according to the invention, the separation points are arranged, for example in a cross shape ,

Due to a deformation of the hat and the concomitant enlargement of the surface, the joints widen and the metallic bright background comes to light. This could probably best recognize the deformation. Also conceivable would be a color marking, for example, sealing wax, which on the one hand firmly adheres but on the other hand, behaves very brittle and already at the slightest mechanical deformation ruptures or partially flakes off.

In 2 is a typical application for such a screw 28 shown, in which, for example, a closure lid not shown in detail may be connected to a likewise not shown in detail loaded with internal pressure tube. For this purpose, usually several screws or threaded bolts are distributed over the circumference of a flange used to make the connection.

This in 2 embodiment shown in FIG 2A a properly executed screw 28 of two component parts 30 . 32 by means of a cap nut formed according to the invention 10 with the interposition of a washer 25 connected bolt 36 with correct supernatant once in plan view and below in longitudinal section.

This projects beyond the bolt 36 the threaded hole 18 the cap nut according to the invention 10 by about 2 threads, which meets the minimum requirements of the valid standards, for example DIN 78 , corresponds. The remaining distance to the nose 22 This is sufficiently large to handle tolerances. However, this distance is limited by the fact that a common nut is used to tighten the cap nut, which has only a defined depth for receiving the hexagon. Accordingly, the distance to the inventively provided nose 22 in the dome-shaped cover 20 limited interior 23 Although short but sufficiently large, so no contact with screw 18 and nose 22 he follows.

This is also due to the undamaged mark 26 at the end face of the cap nut 10 in 2A to recognize.

On the other hand, the in 2 B screwing shown 34 , which in itself is identical to the arrangement according to 2A is and also a top view and below a longitudinal section reproduces a threaded bolt 38 on, in which the projection on the threaded hole 18 so big is that the bolt 38 the nose 22 in the dome-shaped cover 20 limited interior 23 contacted and as a result of the screw-related predisposition thereby dome-shaped cover 20 deformed.

Accordingly, the mark 26 on the face of the cap nut 10 damage due to the deformation described above 27 on, in which the original, cross or star-like mark has expanded starting from the center. This expansion 27 signals the responsible installer or the responsible supervisor that the depth of engagement of the bolt used 38 is greater than allowed for the intended screw, which at the same time says that this screw is not sufficiently secure.

If such a faulty installation occurs, this has the following consequences: The tightening torque is applied to the cap nut in the conventional manner in full height. However, the normally achievable by the tightening torque biasing force is not fully achieved. That means the two component parts 30 . 32 not be compressed with the required force.

Now occurs a stress on the screw 34 according to the operating load, for example by filling a pressure vessel with gas, so the biasing force can not fully counteract the gas power. The component parts 30 . 32 From a certain pressure, they would at least stand out from each other and spatially form a gap. This would lead to a gas leak.

In 3 after all, it's a variation 11 the nut according to the invention 10 according to 1 shown in half-side longitudinal section, which is intended for screw, for which special requirements apply.

If, for example, system components to be connected are exposed to corrosive media, for example in the chemical industry, it must be ensured that the screw holes are sealed on both sides in order to protect the sealing surfaces against corrosion.

For this reason, in a further improvement of the invention according to 3 provided to the main body 16 molded flange with an insert sealing ring 40 to provide, which ensures the greatest possible tightness of the screw or the screw hole.

As an alternative to an insert sealing ring, a firmly integrated sealing ring can be provided instead, which is glued or vulcanized onto the parent material.

In addition, however, it is also expedient to cover the thread projections of the jeweligen bolt 36 to prevent contamination and corrosion. To meet these requirements, the use of cap nuts, which through their hat-like dome shaped cover offers 20 complete the screw connection to the outside.

However, this is certainly true only if the protrusion of the screwed threaded bolt does not exceed the (usual length of about two threads.) According to the invention, the space enclosed by the dome-shaped cover is dimensioned such that the prescribed projection of 2 × P (with P = Thread pitch) is safely maintained by providing about 3-4 x P before the nut goes to block, and if the projection of the bolt bolt is larger, the problem already described above is that the bolt may not provide the required strength of the connection so that it is not sufficiently secure and thus the required tightness is not guaranteed.

This is where the invention starts. By applying the invention, this problem can be avoided, because with a correct screw connection is between the bolt and the screwed into the threaded hole bolts 36 sufficient space so that the required tightening torque can be applied easily to ensure the required tightness and / or strength of the screw connection.

However, if the bolt used 38 too long, that is the supernatant of the screw bolt screwed into the threaded hole 38 is bigger than the one inside 23 the dome-shaped cover 20 available space, it comes to the mechanical loading of inventively provided in the interior 23 protruding nose 22 through the thread projection, whereby the end face of the relevant cap nut according to the invention 10 according to the penetration depth of the bolt 38 coaxially urged to the outside and the dome-shaped Anformung 20 at least deformed, if not destroyed.

The advantages achieved by the invention are, in particular, that the advantages of cap nuts, such as protecting the thread projections from contamination or corrosion or the risk of injury to persons, can also be used for applications for which previously due to an increased security risk, the use of Cap nuts was excluded.

The invention does not serve the purpose of replacing required constructive interpretations with respect to the length of screws and threaded bolts, but rather allows for the occurrence of an unacceptably large protrusion of screws as an exceptional case that this error is detected by the invention early during assembly.

The installer now offer different remedies to correct the error. For example, he can replace the screw that is too long with a shorter screw, or use a standard nut instead of a cap nut for this screw connection. This makes the invention simple and universally applicable.

LIST OF REFERENCE NUMBERS

10

nut according to the invention (cap nut)

12

right half

14

left half

16

body

18

threaded hole

20

dome-shaped cover (hat)

22

nose

23

inner space

24

flange

25

Washer (in 2 )

26

mark

27

widening

28

screw

30

component part

32

component part

34

screw

36

bolt

38

bolt

40

seal

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 787154 A [0003]
• DE 4408733 A1 [0004]
• DE 4239583 C2 [0004]

Cited non-patent literature

• DIN 78 [0012]
• DIN 78 [0050]

Claims (11)

Nut ( 10 ) with a polygonal basic body ( 16 ) with a central bore ( 18 ), which is provided with an internal thread, and with a dome-shaped cover ( 20 ), which coaxial with the central inner bore ( 18 ) on one side of the main body ( 16 ) is formed and has an inner diameter which is at least as large as the internally threaded central bore ( 18 ), characterized in that the dome-shaped cover ( 20 ) on its inside with a nose-shaped Anformung ( 22 ), which is arranged coaxially to the central bore and in which of the dome-shaped cover ( 20 ) limited interior space ( 23 ) protrudes. Nut according to claim 1, characterized in that the dome-shaped cover ( 20 ) with the Anformung provided on the inside ( 22 ) is integrally formed thereon. Nut according to claim 1, characterized in that the dome-shaped cover ( 20 ) with the Anformung provided on the inside ( 22 ) is attached thereto non-positively and / or positively. Nut according to one of the preceding claims 1 to 3, characterized in that the dome-shaped cover ( 20 ) with a display mark ( 26 ) which is connected to the inside of the dome-shaped cover ( 20 ) Anformung ( 22 ) and, when acting on the dome-shaped cover ( 20 ) Anformung ( 22 ) by a bolt ( 38 ) emerges outwardly with oversized screw-in length to indicate a protrusion of a screwed-in threaded element, such as a screw, threaded pin or threaded bolt. Nut according to one of the preceding claims, characterized in that the dome-shaped cover ( 20 ) with a mark ( 26 ), which due to the application of the dome-shaped cover ( 20 ) Anformung ( 22 ) by a bolt ( 38 ) visibly changed with oversized screw length, for example, widens, and so too large a protrusion of a screwed threaded element, such as screw, threaded pin or threaded bolt indicates. Nut according to one of the preceding claims, characterized in that the polygonal basic body ( 16 ) is designed as a hexagon. Nut according to one of the preceding claims, characterized in that the nose-shaped Anformung ( 22 ) on the inside of the dome-shaped cover ( 20 ) is integrally formed. Nut according to one of the preceding claims, characterized in that the polygonal basic body ( 16 ) at its dome-shaped cover ( 20 ) opposite end face with a flange-like extension ( 24 ), whereby the bearing surface of the nut ( 10 ) is enlarged. Nut according to claim 8, characterized in that the bearing surface of the flange-like extension ( 24 ) is provided with a corrugation or ribbing, which is effective as a positive locking screw. Nut according to one of the preceding claims, characterized in that on the dome-shaped cover ( 20 ) opposite end face a sealing ring is arranged, which is inserted or permanently attached to the screw. Screw connection with a nut according to one of the preceding claims, characterized in that on the inside of the dome-shaped cover ( 20 ) Anformung ( 22 ) from a bolt ( 38 ) with one in the main body ( 16 ) provided threaded hole ( 18 ) exceeding engagement length is positively acted upon and that the bolt ( 38 ) thereby the dome-shaped cover ( 20 ) deformed.

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